1. Field of the Invention
The present invention relates to a multilayer electronic part, a method of producing the multilayer electronic part, and more particularly, to a multilayer electronic part (and a method of producing same) in which a plurality of outer electrodes are disposed on only the main surfaces of a multilayer body, and an end face of the multilayer body serves as a mounting surface for mounting the part on a mounting substrate.
2. Description of the Related Art
Multilayer electronic parts which utilize chip capacitors and chip inductors are essential in obtaining miniaturization and higher performance of electronic devices. There is a demand for increased density and performance of such devices and, in response to this demand, a chip capacitor has been proposed in Japanese Patent Publication No. 57-56217.
FIG. 5 is a perspective view of such a chip capacitor 50. Chip capacitor 50 comprises a multilayer body 52 composed of a plurality of stacked sheet layers 51 made of ceramics; inner electrodes 53 made of copper or the like inside the multilayer body 52; and outer electrodes 54 disposed on an end face of the multilayer body 52. In this case, the inner electrodes 53 are connected to the outer electrodes 54 by lead electrodes 55 formed at the ends of the inner electrodes 53. Although not shown, the end face of the multilayer body 52 where the outer electrodes 54 are disposed serves as a mounting surface of the chip capacitor 50, and the chip capacitor 50 is mounted on a printed board by connecting the outer electrodes 54 to a pad on the printed board using solder or the like.
In multilayer electronic parts employing the above-described conventional chip capacitor, however, since the outer electrodes are formed on the end face of the multilayer body, it is necessary, in producing the chip capacitor, to cut a mother multilayer body into individual multilayer bodies and to subsequently form outer electrodes on an end face, which is the cutting face, of the individual multilayer bodies.
As a result, the following problems arise:
1) The production process is complicated and, therefore, the production cost is high.
2) The cutting surface is not sufficiently flat, and it is difficult as a result to provide a narrow a space between the outer electrodes.
3) It is also difficult to measure the characteristics of individual multilayer electronic parts in the assembled state.
To overcome the above described problems, preferred embodiments of the present invention provide a multilayer electronic part that allows low production costs and narrowing of the space between outer electrodes, and a method of producing the multilayer electronic part.
One embodiment of the present invention provides a multilayer electronic part comprising: a multilayer body composed of a plurality of stacked sheet layers made of ceramics, said plurality of stacked sheet layers defining a stacking direction substantially perpendicular to a main surface of each of said plurality of stacked sheet layers; a plurality of inner electrodes and connecting means provided inside said multilayer body; and a plurality of outer electrodes disposed on only a main surface of said multilayer body so as to be electrically connected to any of said inner electrodes via said connecting means, and said multilayer body further comprising a mounting surface so that said multilayer body is mounted at said mounting surface, said mounting surface being substantially parallel to said stacking direction.
Another embodiment of the present invention provides a method of producing a multilayer electronic part comprising the steps of: preparing a plurality of mother sheet layers made of ceramics; forming inner electrodes and connecting means on any one of said plurality of mother sheet layers; forming a mother multilayer body by stacking and press-bonding said plurality of mother sheet layers; forming an outer electrode on only a main surface of said mother multilayer body so as to be electrically connected to any one of said inner electrodes via said connecting means; cutting said mother multilayer body into a multilayer body having said inner electrode, said outer electrode, and said connecting means; and baking said mother multilayer body or said multilayer body.
According to the multilayer electronic part of the present invention, since the outer electrode is disposed on only the main surface of the base plate, it can be formed such that the mother multilayer body is not yet cut in the process of producing the multilayer electronic part.
According to the method of producing a multilayer electronic part of the present invention, since the method includes the step of forming outer electrodes on the main surface of the mother multilayer body, it is possible to narrow the space between the outer electrodes.
Further objects, features, and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.